System and method for providing improved geocoded reference data to a 3d map representation

ABSTRACT

Described are a system ( 200 ) and method arranged to provide improved geocoded reference data to a 3D map representation. The system comprises a storage ( 201 ) having stored thereupon a 3D map representation comprising a textured 3D representation provided with geocoded reference data and formed based on imagery, the imagery being associated to information relating to at least one imaging device which has captured the imaging. The system comprises further a processor ( 208 ) arranged to receive at least one new image associated to information related to an imaging device which has captured the new image, perform registration of the new image to the 3D map representation, determine corresponding points in the new image and the 3D map representation, and determine displacement data for a plurality of 3D positions in the 3D map representation based on the determined corresponding points in the new image and the 3D map representation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to and thebenefit of U.S. patent application Ser. No. 17/164,013, filed Feb. 1,2021, which application further claims priority to and the benefit ofEuropean Patent Application No. 21153822.8, filed on Jan. 27, 2021; thecontents of both of which as are hereby incorporated by reference intheir entireties.

BACKGROUND Related Field

The present invention relates to a system and method for providingimproved geocoded reference data to a 3D map representation.

Related Art

A fast growing market both in civilian and military business isgeographical information systems. Knowledge about geographicalconditions forms a fundamental decision support to companies,authorities and in the military. The geographical information cancomprise digital maps having superposed information layers such asinfrastructure, terrain type and different types of objects.

3D map representation may be formed for example based on processing ofat least partly overlapping images. It is a challenge to provide 3Dgeocoded reference data to such 3D map representations, which 3Dgeocoded reference data corresponds to the real world.

BRIEF SUMMARY

According to a first aspect of the present invention, a system isarranged to provide improved geocoded reference data to a 3D maprepresentation. The system comprises a storage having stored thereuponsaid 3D map representation. The 3D map representation comprises for eachof at least one geographical area, a textured 3D representation providedwith geocoded reference data and formed based on imagery provided forthat geographical area, said imagery being associated to informationrelating to at least one imaging device which has captured the imagery,said information comprising intrinsic and extrinsic parameters of saidat least one imaging device. The system comprises a processor arrangedto receive at least one new image associated to information related toan imaging device which has captured the new image, said informationcomprising intrinsic and extrinsic parameters of the imaging device,determine that the new image belongs to at least one of the at least onegeographical areas, perform registration of the new image to the 3D maprepresentation, determine corresponding points in the new image and the3D map representation, and determine displacement data for a pluralityof 3D positions in the 3D map representation based on the determinedcorresponding points in the new image and the 3D map representation.

Thus, displacement data is determined for a plurality of 3D positions inthe 3D map representation from comparison between the determinedcorresponding points in the new image and the 3D map representation.

In an embodiment, the processor is arranged to modify the 3D maprepresentation with the determined displacement data for the pluralityof 3D positions.

Thus, improved geocoded reference data is provided to the 3D maprepresentation without re-calculating the 3D map representation or partsthereof. This has the effect that limited processing capacity isrequired for taking into account new images in the 3D maprepresentation. Thus, improved geocoded reference data of new images canquickly be implemented in the 3D map representation.

The determination of displacement data for a plurality of 3D positionsin the 3D map representation for a plurality of 3D positions in the 3Dmap representation may comprise weighting the influence from the newimage against the influence from the 3D map representation.

The weighting of the influence from the new image against the influencefrom the 3D map representation may be based on at least one of thefollowing: the specification of the imaging device(s) used, and/orreliability of relevant intrinsic and/or extrinsic parameters of therespective imaging device(s) used for the 3D map representation and/orthe new image.

The imagery and/or new image may be LIDAR and/or RADAR and/or imagescaptured with a camera.

In different embodiments, the imaging comprises an image set comprisingat least partly overlapping images belonging to the geographical area,each image of the image set being associated to the information relatingto the imaging device which has captured the image, said informationcomprising intrinsic and extrinsic parameters of the imaging device.Determining corresponding points in the new image and the 3D maprepresentation may then comprise performing bundle adjustments betweenthe new image and each image of the image set at least partlyoverlapping with the new image.

In different embodiments, the 3D map representation further comprises 3Drepresentation uncertainty data for a plurality of 3D positions in the3D representation, said uncertainty data defining an uncertaintydistance and direction, wherein the determination of displacement datafor a plurality of 3D positions in the 3D map may comprise weighting theinfluence from the new image against the influence from the 3D map basedon the uncertainty data.

The processor may be arranged to calculate updated 3D representationuncertainty data based on the displacement data, wherein the updated 3Drepresentation uncertainty data may be stored as part of the 3D maprepresentation.

In different embodiments, the system further comprises an interface toan application system, said interface being operatively connected to thestorage having stored thereupon the 3D map representation.

The system may be arranged to provide the 3D position data for at leasta part of the 3D map representation at request from the applicationsystem via the interface.

The processor may further be arranged to re-calculate the 3D maprepresentation based on the imaging and the at least one new image. Thischaracteristically is a more demanding with regard to processing thandetermining the displacement data. Therefore, re-calculating the 3D maprepresentation may be made less frequently than the determination of thedisplacement data. Further, the determination of displacement data maybe made when processing capacity is not available for re-calculating the3D map representation. Re-calculation of the 3D map representation maythen be made when processing capacity is available.

The processor may be arranged to identify whether to make are-calculation of the 3D map representation based on the displacementdata. Thus, the processor may be arranged to re-calculate selected partsof the 3D map representation, wherein the selection is made based on thedisplacement data.

The images of the image set and/or new image(s) may comprise satelliteimages captured from one or a plurality of satellites.

The 3D representation may comprise a textured, georeferenced mesh.

When the 3D map representation comprises a textured 3D representationfor a plurality of geographical areas, the processor may be arranged todetermine whether the new image belongs to at least two geographicalareas and when it has been determined that the image belongs to at leasttwo geographical areas and thus forms a bridge between said twogeographical areas, the processor is arranged to determine displacementdata for a plurality of 3D positions in the textured 3D representationsbelonging to the two geographical areas based on the determinedcorresponding points in the new image and the textured 3Drepresentations belonging to the two geographical areas.

The present disclosure further relates to a method for providingimproved georeferenced position data to a 3D map representation, said 3Dmap representation comprising for each of at least one geographicalarea, a textured 3D representation provided with geocoded reference dataand formed based on imagery provided for that geographical area, saidimagery being associated to information relating to an imaging devicewhich has captured the imagery, said information comprising intrinsicand extrinsic parameters of the imaging device, said method comprisingthe steps of: receiving at least one new image associated to informationrelated to an imaging device which has captured the new image, saidinformation comprising intrinsic and extrinsic parameters of the imagingdevice, determining that the new image belongs to at least one of the atleast one geographical areas, performing registration of the new imageto the 3D map representation, determining corresponding points in thenew image and the 3D map representation, and determining displacementdata for a plurality of 3D positions in the 3D map representation basedon the determined corresponding points in the new image and the 3D maprepresentation.

The present disclosure further relates to a computer program forproviding improved georeferenced position data to a 3D maprepresentation, comprising instructions which, when executed by at leastone processor cause the at least one processor to carry out the methodabove.

The present disclosure further relates to a computer-readable storagemedium carrying a computer program for providing improved georeferencedposition data to a 3D map representation according to the above.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following description of various and preferred embodiments,reference will be made to the attached drawings on which:

FIG. 1 is a flow chart illustrating an example of a method for providingimproved georeferenced position data to a 3D map representation;

FIG. 2 is a block scheme illustrating an example of a system forproviding improved georeferenced position data to a 3D maprepresentation;

FIG. 3 shows schematically the capture of images of an area on theground using a satellite and an aircraft;

FIG. 4 shows schematically how a part of the globe may be covered by aplurality of areas on the ground, wherein each area may be covered by aplurality of images;

FIG. 5 illustrates an example of a 3D map representation;

FIG. 6 illustrates schematically a mesh; and

FIG. 7 illustrates schematically a mesh uncertainty.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

In the following description the same reference numerals will be usedfor similar features in the different drawings. The drawings are notdrawn to scale.

In FIG. 1, an example of a method 100 for providing improvedgeoreferenced position data to a 3D map representation is illustrated.The 3D map representation comprises for each of at least onegeographical area, a textured 3D representation provided with geocodedreference data. The 3D map representation is formed based on imageryprovided for that geographical area. The imagery is associated toinformation relating to an imaging device that has captured the imaging.The information relating to the imaging device comprises intrinsicand/or extrinsic parameters of the imaging device. The informationcomprises for example a geographical 3D position of the imaging deviceand/or a pointing direction and/or Field-of-View of the imaging device.

The method may start with a step of providing 110 the 3D maprepresentation.

The method comprises receiving 120 at least one new image associated toinformation related to an imaging device which has captured the newimage, said information comprising intrinsic and extrinsic parameters ofthe imaging device. The new image may have characteristics which areconsidered to improve the georeferenced position data of the 3D maprepresentation if included in the 3D map representation. For example,the new image may have been captured using an imaging device, thepointing direction of which is known with a high accuracy,characteristically higher that the accuracy of the pointing directionconnected to the imaging devices on which the 3D map representation wasformed.

The method comprises determining 130 that the new image belongs to atleast one of the at least one geographical areas. The 3D maprepresentation may comprises a textured 3D representation for aplurality of geographical areas. It may then be determined 130 whetherthe new image belongs to at least one of the geographical areas. It mayin addition thereto be determined whether the new image belongs to atleast two geographical areas.

The method comprises performing 140 registration of the new image to the3D map representation. This is known in the art and not described indetail herein. For example, this is described in WO 2014/112909. Themethod comprises thereafter a step of determining 150 correspondingpoints in the new image and the 3D map representation.

The imagery may comprise an image set comprising at least partlyoverlapping images belonging to the geographical area. As mentionedabove, each image of the image set is associated to the informationrelating to that imaging device which has captured the image, saidinformation comprising intrinsic and extrinsic parameters of the imagingdevice. The determining step 150 for determining corresponding points inthe new image and the 3D map representation may then comprise performingbundle adjustments between the new image and each image of the image setat least partly overlapping with the new image.

The method comprises further a step of determining 160 displacement datafor a plurality of 3D positions in the 3D map representation based onthe determined corresponding points in the new image and the 3D maprepresentation.

The displacement data provides improved geocoded reference data to the3D map representation.

The step of determining 160 displacement data for a plurality of 3Dpositions in the 3D map representation may comprise weighting theinfluence from the new image against the influence from the 3D maprepresentation. The weighting of the influence from the new imageagainst the influence from the 3D map representation may be based onuncertainty data relating to the 3D map representation and/or relatingto the new image.

The uncertainty data may characteristically define an uncertaintydistance and direction.

The uncertainty data may depend on at least one of the following: thespecification of the imaging device(s) used for the 3D maprepresentation and/or the new image (including intrinsic and/orextrinsic parameters), reliability of relevant intrinsic and/orextrinsic parameters of the respective imaging device(s) used for the 3Dmap representation and/or the new image, and/or the number of imagesused in the 3D map representation for modelling the area covered by thenew image.

In an example, when the imaging comprises an image set comprising atleast partly overlapping images belonging to the geographical area, thestep of determining 160 displacement data for a plurality of 3Dpositions in the 3D map representation may comprise weighting theinfluence from the new image against the influence from the 3D map basedon the number of images used in the 3D map representation for modellingthe area covered by the new image.

In an additional or alternative example, the three dimensional geocodedreference data of the 3D map representation may for a plurality of 3Dpositions in the 3D representation further comprise 3D representationuncertainty data. The uncertainty data may, as stated above, define anuncertainty distance and direction. The step of determining 160displacement data for a plurality of 3D positions in the 3D maprepresentation may then comprise weighting the influence from the newimage against the influence from the 3D map representation based on theuncertainty data. Thus, if the three-dimensional geocoded reference dataof the 3D map representation is uncertain, then the new image can have abigger influence than if the uncertainty in the 3D map representation islow.

The method may comprise a step of modifying 170 the 3D maprepresentation with the determined displacement data for the pluralityof 3D positions. For example, when the 3D map representation comprises3D representation uncertainty data for a plurality of 3D positions inthe 3D representation, updated 3D representation uncertainty data mayalso be determined based on the displacement data, wherein the updated3D representation uncertainty data may be stored as part of the 3D maprepresentation.

When the 3D map representation comprises a textured 3D representationfor a plurality of geographical areas, and it has been determined thatthe new image belongs to at least two geographical areas thus forms abridge between said two geographical areas, displacement data may bedetermined 160 for a plurality of 3D positions in the textured 3Drepresentations belonging to the two geographical areas based on thedetermined corresponding points in the new image and the textured 3Drepresentations belonging to the two geographical areas. Then this newimage is contributing to linking different geographical areas togetherand thus contributing to providing a globally continuous and accurate 3Dmap representation.

The method further comprises re-calculating 190 the 3D maprepresentation based on the imagery and the at least one new image. Themethod may comprise identifying 180 whether to make the re-calculation190 of the 3D map representation based on the displacement data.Further, when the 3D map representation comprises 3D representationuncertainty data and/or updated 3D map representation uncertainty data,the step of identifying 180 whether to make a re-calculation 190 of the3D map representation may instead or in addition thereto be based on theuncertainty data. When the 3D map representation has been recalculated,the uncertainty data is characteristically also updated to relate to therecalculated 3D map representation.

In FIG. 2, an example of a system 200 arranged to provide improvedgeocoded reference data to a 3D map representation is illustrated. Thesystem 200 comprises a storage 201 having stored thereupon said 3D maprepresentation 202. The 3D map representation comprises for each of atleast one geographical area, a textured 3D representation provided withgeocoded reference data. The 3D map representation 202 is formed basedon imaging provided for that geographical area. The 3D representationprovided with geocoded reference data may comprise a textured,georeferenced mesh. Alternatively, the 3D map may be represented as asurface representation, or as a voxel representation.

In the illustrated example, the storage 201 has an imagery data storagepart 203 in which at least a part of the imagery is stored. The imageryis associated to information relating to an imaging device that hascaptured the images, said information comprising intrinsic and extrinsicparameters of the imaging device. The information 205 relating to animaging device that has captured the imagery is also stored in thestorage 201.

Further, the system 200 further comprises an interface 206, by means ofwhich new images are received. The new images may be stored in imagedata storage part 203 together with information 205 related to animaging device that has captured the new image, said informationcomprising intrinsic and extrinsic parameters of the imaging device.

In the illustrated example, imaging device(s) 207 used for capturing atleast some of the imagery and/or new images are illustrated as optionalpart of the system. The imaging devices may be satellite based and/oraircraft based and/or land based. However, it is not important how theimaging data and/or new images are obtained. The important thing thatimagery data/new images 203 and imaging device information 205 is storedin the data storage 201.

The system 200 comprises further a processor 208 arranged to receive atleast one new image associated to information related to that imagingdevice which has captured the new image, said information comprisingintrinsic and extrinsic parameters of the imaging device, determine thatthe new image belongs to at least one of the at least one geographicalareas, perform registration of the new image to the 3D maprepresentation, determine corresponding points in the new image and the3D map representation, and determine displacement data for a pluralityof 3D positions in the 3D map representation based on the determinedcorresponding points in the new image and the 3D map representation. Theprocessor may be arranged to operate as discussed in relation to theflow chart of FIG. 1.

The determined displacement data may be stored 204 in the data storage201.

The processor 208 may further comprises a program code for calculatingthe 3D map representation. Further, a memory may be arranged to store acomputer program comprising a program code for performing the method asdisclosed herein.

The system 200 may further comprise an interface 209 to an applicationsystem, said interface being operatively connected to the storage havingstored thereupon the 3D map representation. The system 200 may bearranged to provide the 3D position data, displacement data, whenavailable, and/or modified 3D position data for at least a part of the3D map representation at request from the application system via theinterface 209.

The system 200 may be implemented on a server device. The server devicemay comprise a first input for a 3D map representation and a secondinput for images. The server device also comprises the processor onwhich a computer program runs, which makes the server device to performthe method as, disclosed herein.

In the example of FIG. 3, capture of images of an area on the ground 1using a first satellite 10 and a second satellite 11 is schematicallyshown. As is shown in FIG. 1 the first satellite 10 captures a firsttwo-dimensional (2D) satellite image of a first area 2 from a firstangle and the second satellite 11 captures a second two dimensional (2D)satellite image of the first area 2 from a second angle.

Each one of the 2D satellite images is associated with informationrelated to the imaging device that has captured the imagery, saidimagery comprising intrinsic and/or extrinsic parameters of the imagingdevice. The intrinsic and/or extrinsic parameters may comprise apointing direction of the satellite data and/or distance informationindicating a distance from the satellite to the ground and/or ageographical position of the satellite. A 3D map representationcomprising geocoded reference data and texture is generated from the 2Dsatellite images, using the information related to the imagingdevice(s).

Generally, a set of images is provided wherein the images have beencaptured by the at least one camera. The set of images comprises a firstimage captured with the at least one camera is directed in a firstdirection in the first area 2. The set of images comprises a secondimage captured with the at least one camera directed in a seconddirection to the first area 2. The image set comprises a plurality of atleast partly overlapping images each covering at least a part of thearea 2.

The generation of a 3D map representation from 2D images is known fromthe prior art. Generation of a 3D map from 2D images comprises generallythe steps of providing a plurality of overlapping images of an area anddeveloping the 3D model based on the plurality of overlapping images.This will be more discussed in relation to FIG. 5.

Imagery using aerial or satellite images is often referred to as air- orspace-born imagery.

FIG. 4 illustrates how a part of the globe may be covered by capturingimage sets for a plurality of, in this case six, different areas 2 a-2 fof the ground, which areas may or may not be slightly overlapping eachother. This makes it possible to fit the captured images to each other.At least 2 satellite test images are captured of each area 2 a-2 f.

FIG. 5 illustrates a 3D map representation 9 comprising geocodedreference data and texture information on the lower right part 7 of themap and comprising only geocoded reference data on the upper left part 8of the map. After generation of the geocoded reference data the 3D map 9looks like the upper left part 8 of the 3D map 9. The textureinformation is then applied by for example using the texture of at leastsome of the 2D images or to create a 3D map 9 as is shown in the lowerright part 7.

As discussed above, processing of the at least partly overlapping imagesof an image set belonging to an area to provide the 3D maprepresentation comprises finding corresponding points in the at leastpartly overlapping images and to find disparity estimations based on thecorresponding points. In an example, for each image to be processed, ageocoded reference data position is provided to each or a plurality ofthe pixels of each image. The processing is then performed based on theassociated geocoded reference data so that the pixels in the 3D maprepresentation are also specified in three geographical dimensions.

The forming of the 3D map representation based on at least partlyoverlapping images comprises performing bundle adjustment. Given a setof images depicting a number of 3D points from different viewpoints,bundle adjustment can be defined as the problem of simultaneouslyrefining the 3D coordinates describing the scene geometry as well as theparameters of the relative motion and the optical characteristics of thecamera(s) employed to acquire the images, according to an optimalitycriterion involving the corresponding image projections of all points.

There are a different ways of representing the 3D map. The 3D map may berepresented as a mesh, as a surface representation, or as a voxelrepresentation.

The 3D map representation may be provided based on other informationthan camera images. For example, the 3D map representation may beprovided based on any type of distance measurements. For example,example LIDAR, sonar, distance measurement using structured light and/orradar can be used instead of or in addition to measurements based oncamera images. The camera for example can be a camera for visual lightor an IR camera.

For example, processing may be performed to provide the results of aplurality of distance measurements to each area from a plurality ofgeographically known positions using a distance determining device. The3D map representation is then provided for each area based on theplurality of distance measurements.

In the illustrated example, the 3D map is represented as a mesh. Aprocessor is arranged to form the mesh based on the map representationspecified in the three geographical dimensions. Further, textureinformation from the original images may be associated to the surfacesof the mesh. In detail, the processor is arranged to form the mesh byforming nodes interconnected by edges forming surfaces defined by theedges, wherein each node is associated to a three-dimensional geocodedreference data in a geographical coordinate system.

In FIG. 6, a 3D map representation is formed as a mesh 600. The mesh 600comprises a plurality of nodes 101 interconnected by means of edges 102.Surfaces 103 are provided boarded by the edges 102 of the mesh 600. Thenodes 101 are each associated to a 3D coordinate in a geographicalcoordinate system. The surfaces 103 are in one example each associatedto texture information. In one example, the surfaces are also eachassociated to 3D coordinate data in the geographical coordinate system.Further, a mesh uncertainty is associated to at least a subset of thenodes of the mesh. The mesh uncertainty associated to each respectivenode represents the uncertainty at that specific point of the model. Inone example, the mesh uncertainty is associated to each node of themesh. Determination of a mesh uncertainty is for example discussed inWO2014/112908.

Instead, or in addition thereto, at least a subset of the surfacesand/or edges can be associated to a mesh uncertainty. In one example,one mesh uncertainty is associated to each surface and/or edge.Alternatively, each surface and/or edge is associated to a plurality ofmesh uncertainty values. For example, the mesh uncertainty values of theedges/surfaces are determined based on interpolation betweenneighbouring nodes.

In FIG. 7, the mesh uncertainty is illustrated. A value 700 for the meshuncertainty is given in at least two directions. In the illustratedexample, the mesh uncertainty value 700 is given in two dimensions. Theuncertainty value in each direction is in one example represented as adistance or another value related to the distance. In one example, theuncertainty is represented as a value and possibly also direction in theplane of the surface and as a value in a direction perpendicular to theplane of the surface. In accordance with this example, each uncertaintyis represented in relation to the associated local plane given by thesurface of the mesh. When the uncertainty is given in space, theuncertainty defines an ellipsoid, the size and shape of which is givenby the uncertainty value in each respective direction. In one examplewhen the mesh uncertainty is given in three dimensions, it isrepresented as a 3×3 matrix. In one example when the mesh uncertainty isgiven in two dimensions, it is represented as a 2×2 matrix. Theuncertainty may be represented as a probability.

Below follows some detailed examples of how uncertainty information canbe provided.

The position of the at least one imaging device in the geographicalcoordinate system may for example be determined using a satellite basedpositioning system, such as GPS. The positioning of the imaging devicecan then be determined based on information provided from satellites ofthe satellite based positioning system. Uncertainty information may forexample be based on the number of satellites used for determining theposition of imaging device.

The mesh uncertainty may instead or in addition thereto be determinedbased on an uncertainty in the position and direction of the opticalaxis of the at least one imaging device. In accordance therewith, apositioning system is arranged to provide uncertainty information inthree dimensions (x, y, z, and three associated angles). The directionof the optical axis of the imaging system can then be determined basedon the information provided from the positioning system. The positioningsystem comprises in one example an inertial navigation system.

The mesh uncertainty may instead or in addition thereto be determinedbased on an imaging uncertainty of the imaging device. For example, theimagining uncertainty of the imaging device can comprise an uncertaintyrelated to the field of view of the imaging device. Further, theimagining uncertainty of the imaging device can comprise an uncertaintyrelated to the optical axis of each of the pixels of the camera. Theimaging uncertainty of the camera may then be determined based on the atleast one of the above uncertainties. Errors in the field of view and/orthe direction of the pixels of the camera can be modelled andcompensated for but still there is an imaging uncertainty based onerrors in the model of the camera. The errors in the field of viewand/or direction of the pixels or the camera are characteristicallytemperature dependent.

The processor may in addition thereto or instead be arranged todetermine the number of images available for use in modelling a certainarea and determining the mesh uncertainty based on the number of imagesavailable for the certain area. If let us say twenty images is availablefor a certain area, this indicates that this area or point is visiblefrom many directions and thus easier to model. If on the other hand thepoint or area is visible in much fewer images, or example two to four,this point or area is more difficult to model correctly.

Further, the processor may be arranged to determine the spatial relationbetween the images available and to determine the mesh uncertainty basedon the spatial relation between the images available. For example, ifimages are only available from a narrow angle, the uncertainty is biggerthan if images are available from a wide angle. Further, if only imagestaken from a long distance are available, the uncertainty is bigger thanif there are images available from a narrow distance. Further, if theimages are taken from an angle substantially perpendicular to thesurface to be modelled the uncertainty is smaller than if the image istaken almost in parallel with the surface to be modelled. The samereasoning applies when the model is built up from information fromdistance measurement devices.

In one example, the uncertainty of the mesh can in addition thereto orinstead be determined based on comparing an image I₂ taken from onecertain location with an estimated image Î₂ determined for the samecertain location. The estimated image is determined based on anotherimage I₁ taken from another location and projected in the 3D model tothe position to the location of the image I₂. Thus the estimated imageis determined as Î₂=f(I₁ M), wherein M represents the 3D model. Incomparing the image I₂ taken from the certain location with theestimated image Î₂ for that certain location determined based on anotherimage I₁ taken from another location, the similarity between the imageand the estimated image can be compared. In one example, the images arecompared on a point by point basis. Based on discrepancies between theimages, it can then be identified if for example certain objects in themodel are erroneously modelled. These errors in the model are in oneexample contained in the uncertainty related to each point/edge/surfacein the mesh.

The texture can be removed and replaced with the colour coding based onthe mesh uncertainties. It is then illustrated in which parts of themodel the mesh uncertainties are acceptable and in which parts they arenot. It is then possible for a user of the 3D map representation to knowwhere in the geography the representation is more reliable and where itis less reliable and also providing a measure of the reliability. In oneexample, the texture of the mesh can be presented along with the meshuncertainties. In one example, the texture is presented in black andwhite. The texture may be presented in a semi-transparent manner.

The above described embodiments may be amended in many ways withoutdeparting from the scope of the present invention, which is limited onlyby the appended claims.

1. A system (200) arranged to provide improved geocoded reference datato a 3D map representation, said system (200) comprising: a storage(201) having stored thereupon a 3D map representation, said 3D maprepresentation comprising for each of at least one geographical area, atextured 3D representation provided with geocoded reference data andformed based on imagery provided for that geographical area, saidimagery being associated to information relating to at least one imagingdevice which has captured the imaging, said information comprisingintrinsic and extrinsic parameters of said at least one imaging device,and a processor (208) configured to: receive at least one new imageassociated to information related to an imaging device which hascaptured the new image, said information comprising intrinsic andextrinsic parameters of the imaging device, determine that the new imagebelongs to at least one of the at least one geographical areas, performregistration of the new image to the 3D map representation, determinecorresponding points in the new image and the 3D map representation, anddetermine displacement data for a plurality of 3D positions in the 3Dmap representation based on the determined corresponding points in thenew image and the 3D map representation.
 2. The system according toclaim 1, wherein the 3D map representation is modified with thedetermined displacement data for the plurality of 3D positions.
 3. Thesystem according to claim 2, wherein the determination of displacementdata for a plurality of 3D positions in the 3D map representation for aplurality of 3D positions in the 3D map representation comprisesweighting the influence from the new image against the influence fromthe 3D map representation.
 4. The system according to claim 1, whereinthe determination of displacement data for a plurality of 3D positionsin the 3D map representation for a plurality of 3D positions in the 3Dmap representation comprises weighting the influence from the new imageagainst the influence from the 3D map representation.
 5. The systemaccording to claim 4, wherein the weighting of the influence from thenew image against the influence from the 3D map representation is basedon at least one of: the specification of the imaging device(s) used, orreliability of relevant intrinsic and/or extrinsic parameters of therespective imaging device(s) used for the 3D map representation and/orthe new image.
 6. The system according to claim 1, wherein: the imagerycomprises an image set comprising at least partly overlapping imagesbelonging to the geographical area, each image of the image set beingassociated to the information relating to the imaging device which hascaptured the image, said information comprising intrinsic and extrinsicparameters of the imaging device, and determining corresponding pointsin the new image and the 3D map representation comprises performingbundle adjustments between the new image and each image of the image setat least partly overlapping with the new image.
 7. The system accordingto claim 1, wherein the 3D map representation further comprises 3Drepresentation uncertainty data for a plurality of 3D positions in the3D representation, said uncertainty data defining an uncertaintydistance and direction, wherein the determination of displacement datafor a plurality of 3D positions in the 3D map representation comprisesweighting the influence from the new image against the influence fromthe 3D map representation based on the uncertainty data.
 8. The systemaccording to claim 7, wherein the processor (208) is configured tocalculate updated 3D representation uncertainty data based on thedisplacement data, wherein the updated 3D representation uncertaintydata may be stored as part of the 3D map representation.
 9. The systemaccording to claim 1, wherein: the system further comprises an interface(209) to an application system, said interface being operativelyconnected to the storage having stored thereupon the 3D maprepresentation, and the system is arranged to provide the 3D positiondata for at least a part of the 3D map representation at request fromthe application system via the interface.
 10. The system according toclaim 1, wherein the processor (208) is further configured tore-calculate the 3D map representation based on the imagery and the atleast one new image.
 11. The system according to claim 1, wherein theprocessor (208) is further configured to identify whether to make are-calculation of the 3D map representation based on the displacementdata.
 12. The system according to claim 1, wherein the images of theimage set and/or new image(s) comprise satellite images captured fromone or a plurality of satellites.
 13. The system according to claim 1,wherein the 3D representation provided with geocoded reference data andcomprises a textured, georeferenced mesh.
 14. The system according toclaim 1, wherein when the 3D map representation comprises a textured 3Drepresentation for a plurality of geographical areas, the processor isconfigured to: determine whether the new image belongs to at least twogeographical areas and when it has been determined that the imagebelongs to at least two geographical areas and thus forms a bridgebetween said two geographical areas, and determine displacement data fora plurality of 3D positions in the textured 3D representations belongingto the two geographical areas based on the determined correspondingpoints in the new image and the textured 3D representations belonging tothe two geographical areas.
 15. A method (100) for providing improvedgeoreferenced position data to a 3D map representation, said 3D maprepresentation comprising for each of at least one geographical area, atextured 3D representation provided with geocoded reference data andformed based on imagery provided for that geographical area, saidimagery being associated to information relating to at least one imagingdevice which has captured the imagery, said information comprisingintrinsic and extrinsic parameters of the at least one imaging device,said method comprising the steps of: receiving (120) at least one newimage associated to information related to an imaging device which hascaptured the new image, said information comprising intrinsic andextrinsic parameters of the imaging device, determining (130) that thenew image belongs to at least one of the at least one geographicalareas, performing (140) registration of the new image to the 3D maprepresentation, determining (150) corresponding points in the new imageand the 3D map representation, and determining (160) displacement datafor a plurality of 3D positions in the 3D map representation based onthe determined corresponding points in the new image and the 3D maprepresentation.
 16. A computer program for providing improvedgeoreferenced position data to a 3D map representation, the computerprogram comprising instructions which, when executed by at least oneprocessor cause the at least one processor to carry out the methodaccording to claim
 15. 17. A non-transitory computer-readable storagemedium carrying the computer program according to claim 16 for providingimproved georeferenced position data to a 3D map representation.